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Apache Tomcat

StackGen ObserveNow can pull logs and metrics from Apache Tomcat using the jmx_exporter that can be configured using the StackGen Agent. Please follow the steps below to configure the agent to monitor your Tomcat installation

info

Prerequisite: StackGen ObserveNow Agent installed on the VM running Tomcat following the steps [mentioned here](../../Collecting Telemetry/Install the OpsVerse Agent#dszlx)

Assuming you have the ObserveNow agent up and running on the VM, you can follow the nest steps to configure Tomcat observability

Metrics

Install the JMX Exporter​

# for amd64
curl https://raw.githubusercontent.com/OpsVerseIO/installers/main/prometheus-exporters/install-exporter-amd64.sh | sudo bash -s -- -e jmx  

# for arm64
curl https://raw.githubusercontent.com/OpsVerseIO/installers/main/prometheus-exporters/install-exporter-arm64.sh | sudo bash -s -- -e jmx

Configure JMX Exporter for Tomcat​

Open /etc/opsverse/exporters/jmx/config.yaml and add the following config into it:

lowercaseOutputLabelNames: true
lowercaseOutputName: true
whitelistObjectNames: ["java.lang:type=OperatingSystem", "Catalina:*"]
blacklistObjectNames: []
rules:
  - pattern: 'Catalina<type=Server><>serverInfo: (.+)'
    name: tomcat_serverinfo
    value: 1
    labels:
      serverInfo: "$1"
    type: COUNTER
  - pattern: 'Catalina<type=GlobalRequestProcessor, name=\"(\w+-\w+)-(\d+)\"><>(\w+):'
    name: tomcat_$3_total
    labels:
      port: "$2"
      protocol: "$1"
    help: Tomcat global $3
    type: COUNTER
  - pattern: 'Catalina<j2eeType=Servlet, WebModule=//([-a-zA-Z0-9+&@#/%?=~_|!:.,;]*[-a-zA-Z0-9+&@#/%=~_|]), name=([-a-zA-Z0-9+/$%~_-|!.]*), J2EEApplication=none, J2EEServer=none><>(requestCount|processingTime|errorCount):'
    name: tomcat_servlet_$3_total
    labels:
      module: "$1"
      servlet: "$2"
    help: Tomcat servlet $3 total
    type: COUNTER
  - pattern: 'Catalina<type=ThreadPool, name="(\w+-\w+)-(\d+)"><>(currentThreadCount|currentThreadsBusy|keepAliveCount|connectionCount|acceptCount|acceptorThreadCount|pollerThreadCount|maxThreads|minSpareThreads):'
    name: tomcat_threadpool_$3
    labels:
      port: "$2"
      protocol: "$1"
    help: Tomcat threadpool $3
    type: GAUGE
  - pattern: 'Catalina<type=Manager, host=([-a-zA-Z0-9+&@#/%?=~_|!:.,;]*[-a-zA-Z0-9+&@#/%=~_|]), context=([-a-zA-Z0-9+/$%~_-|!.]*)><>(processingTime|sessionCounter|rejectedSessions|expiredSessions):'
    name: tomcat_session_$3_total
    labels:
      context: "$2"
      host: "$1"
    help: Tomcat session $3 total
    type: COUNTER

Configure Tomcat to use JMX Exporter​

In the same directory where catalina.sh is, create a file named setenv.sh (usually /opt/tomcat/bin/) and add the following into the directory

#! /bin/sh
export CATALINA_OPTS="$CATALINA_OPTS -javaagent:/usr/local/bin/jmx_prometheus_javaagent-1.1.0.jar=9404:/etc/opsverse/exporters/jmx/config.yaml"
tip

Ensure the file is executable using the command chmod +x setenv.sh

Restart Tomcat and in a few seconds you should start seeing Tomcat metrics in the Metrics Explorer in your ObserveNow Grafana

Logs

Configure Observe Agent​

To pull Apache Tomcat logs into ObserveNow, you only need to add a new block to the agent config. Open up /etc/opsverse/agent-config.yaml and under logs -> configs -> scrape_ configs add the following block:

- job_name: tomcat
  static_configs:
    - labels:
        job: tomcat
        host: <hostname> # Add unique hostname
        __path__: /opt/tomcat/logs/* # This path may be different depending on how Tomcat was installed

Restart Observe Agent​

Restart Observe Agent with sudo systemctl restart opsverse-agent and you should see logs in your ObserveNow Grafana under the Logs datasource with the label job = tomcat

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